Haineaultite , Analcime , Natrolite Locality: Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire , Rouville RCM, Montérégie , Québec , Canada ( Locality at mindat.org ) This specimen would be considered a very rich example because of the eye-visible wealth of bright , gemmy yellow crystals present; and comes with a label from Gilles Haineault showing that he collected it in April of 2000. The crystals are not sparse at all and a whole seam of them is easily seen without needed visual aid. The piece has several very sharp crystals to 2mm. 3.5 x 2.9 x 2.1 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Haineaultite
Haineaultite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Na,Ca)₅Ca(Ti,Nb)₅Si₁₂O₃₄(OH,F)₈·5H₂O.
It crystallizes in the orthorhombic crystal system (space group C222).
Key properties: Mohs hardness 3–4; specific gravity 2.28; White streak; Vitreous luster; optically biaxial.
IMA symbol Hnt, IMA status: approved, named in 1997.
A late-stage mineral in altered marble zenoliths and breccia in a complex peralkaline intrusion (nepheline and sodalite syenties).
It is found associated with Quartz, calcite, sodic amphibole, pectolite, fluorapophyllite, vesuvianite, tainiolite, albite, fluorite, microcline, aegirine, and 17 less-abundant minerals.
The mineral was named to honor Gilles Haineault (b. 1946) of St-Mathieu de Beloeil, Quebec, a collector and dealer of minerals from Mont Saint-Hilaire.